Marie Curie - Greer Garson
Pierre Curie - Walter Pidgeon
Eugene Curie - Henry Travers
Prof. Jean Perot - Albert Bassermann
David Le Gros - Robert Walker
Lord Kelvin - C. Aubrey Smith
Madame Eugene Curie - Dame May Whitty
President of University - Victor Francen
Madame Perot - Elsa Bassermann
Dr. Becquerel - Reginald Owen
Reporter - Van Johnson
Irene Curie (at age 5) - Margaret O'Brien
Narrator (voice) - James Hilton
Director - Mervyn LeRoy
Producer - Sidney Franklin
Screenplay - Aldous Huxley, Paul Osborn, Hans Rameau, Walter Reisch
Music - Herbert Stothart and William Axt
Cinematography - Joseph Ruttenberg
Editor - Harold F. Kress
Production and distribution - Metro-Goldwyn-Mayer